ECM Relay?
Thread Starter
|
New User
Joined: Jul 2004
Posts: 4
Likes: 0
ECM Relay?
I have a no start 87 F250 (5.0). Suspect ECM but want to pinpoint first if possible. I can't get error codes from ECM. I have no elec power to fuel pumps, althought they will operate if connected directly. There is no power at any time to the EEC relay and power at all times (Yellow wire only) to the fuel pump relay. No additional power w/key on to either relay. Checked inertia switch and fusible links at elec solenoid. All OK. No initial 2 second power either.
Does EEC relay pick up power from ignition switch, solenoid, or ECM/ What color wire? Grounding fuel pump term on access plug also no response. Does fuel relay receive signal from EEC relay or ECM unit? Also no signal from pin #37 on ECM.
HELP!
Does EEC relay pick up power from ignition switch, solenoid, or ECM/ What color wire? Grounding fuel pump term on access plug also no response. Does fuel relay receive signal from EEC relay or ECM unit? Also no signal from pin #37 on ECM.
HELP!
Lead Driver
Joined: Nov 2002
Posts: 9,555
Likes: 40
From: Concord, NC
I don't think it is the computer. There should be a wire on the ECM relay that is hot all the time. The ECM controls the fuel pumps, so if the ECM is not turning on, then the fuel pumps will not be switched either.
Lead Driver
Joined: Nov 2002
Posts: 9,555
Likes: 40
From: Concord, NC
Well, the yellow wire on the EEC relay should stay 12V all the time. Black is a ground, and the white/light blue is hot when the key is on. I think the power goes back to the starter solonoid where there are fusible links, but I don't know for sure. According to my wiring diagram, the yellow supply power wire on the Fuel pump relay is only hot with the key on, but that doesn't make sense, because it also goes to the keep alive power for the computer which should stay on.
Thread Starter
|
New User
Joined: Jul 2004
Posts: 4
Likes: 0
My yellow to the fuel relay is always hot, but not to the EEC. Since all fuse link test OK, I assumed that EEC picked up power from ECM unit, but perhaps have break in line somewhere else. Would it perhaps pick up power from the ignition switch?
Thread
Thread Starter
Forum
Replies
Last Post
F125Lariat
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
4
Dec 16, 2014 06:38 PM
lars of colorado
1987 - 1996 F150 & Larger F-Series Trucks
8
Dec 8, 2010 09:48 AM
Bayer-Z28
General Automotive Discussion
7
Mar 21, 2010 01:08 PM
bondob
1987 - 1996 F150 & Larger F-Series Trucks
2
Nov 20, 2009 08:24 AM
